Henderson sits next to 4 phonetic neighbors — Anderson, Benson, and Jefferson are the closest matches by sound. Most share Henderson's Scottish cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"son of Hendry (Henry)"
"slender, narrow"
"highlands, uplands"
"sea hill"
"great happiness"
"twin"
"from Laurentum; laurel-crowned"
"he enlightens, God enlightens"
"fisherman"
"royal settlement, king's town"
"first, beginning"
"independent, free-spirited"
"Dutch diminutive form of Adriaan"
"small forest, wooded grove"
"victory"
"dark red, crimson"
"falling, rhythmic beat"
"warrior, strong one"
"nobleman, warrior"
"muddy farm or settlement"
Similar sound: These names share phonetic patterns with Henderson — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Scottish origins, giving them the same cultural heritage as Henderson.
Rhythm: Henderson is a 3-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.